Electric motor.



C. I. HALL.

, ELECTRICMOTOR.

APPLICAYION FILED DEC- 5. I914.

Pzifented July 24, 1917.

Witnesses Inventor Chester 1. Hal I,

His JIttorney.

UNITED STATES PATENT OFFICE.

CHESTER I. HALL. OF FORT WAYNE. INDIANA, ASSI GNOR T0 GENERAL ELECTRIC VCOMPANY, A CORPORATION OF NEW YORK.

ELECTRIC MOTOR.

Specmcafion'of Letters Patent.

Patented July 24,1917.

Application filed December 5, 1914. Serial No. 875,628.

merous apparatus. Electrical demand ap paratus serves as an especiallygood example of aninstance where such substitution is peculiarlyadvantageous. In certain well known t of electrical demand appa ratus, atimee'eping device is necessaryto determine'the equal intervals of timeduring which the demand is measured or to determine the duringwhichequal energy intervals are consumed. A clock for this type ofapparatus should run for at least one month .without' winding, orattention, since the indications or registrations of apparatus of thischaracter are only examined once each month. A spring-actuated clockworkmechanism for the satisfactory operation of commercial demand a paratus've. A satisfactory clock,,such as a constant s eed electric'motor,- isparticularly adapted for electrical 'demand apparatus, since atimekeedeviceofthis character will run with fittle or no attention whenisunreasonably ever it is supplied with the necessary elecric enerThedifiiculty in the provision of a. satis actory electric-motor foroperation as a time-keeping device consists chiefly in providing a motorwhich operates at substantially constant'speed under all normalconditions of a commercial electric circuit. Commercialelectric-circuits are subject to voltage and frequencyfluctuations, andvariations in these two characteristics afl'ect the speed of theordinary types of electric motor. Y

The objectof my present invention is to provide a novel form ofinduction motor adapted to operate at substantially constant speed whensupplied with alternatin currentenergy from'a'commercial electric cir-.cuit. More particularly the object of my invention is to provide anelectric motor of the induction motor type whose speed is substaiitially independent of the ordinary fluctuations of voltageoccurring in commercial electric circuits. Another obj ectof myinvention is to provide means for compensating for changes in speed of amotor occasionedby changes in the surrounding tem erature, andparticularly to provide means or modi fying the torque of the motor inresponse to variations in temperature.

In the embodiment of my invention hereiii illustrated and described, Iprovide a magnetic member having oppositely positioned poles separatedby a small air gap and .a metallic disk armature mounted for I rotationin the air gap. The ma ber is energized by a coil adapte to be connected to a commercial alternating current circuit. The motor dependsfor its'torque upon the phase displacement between 'the leakage fluxcutting the disk armature and etic memthe'main flux between the poles ofthe .mag-

neetic member which also cuts the disk at mature. This torque iscontrolled by the electromagnetic drag generated by the magnecticmember. It is apparent, therefore, that the torque and the electromanetic drag are both dependent upon the va ue of the total fluxgenerated, which renders the motor substantially independent of volriations. An increase of voltage, whi generates'aii increased flu'x,will create a lar value of torque and a pro ortionally large value ofmagnetic drag, t us maintaining substantially constant speed. I obtainclose calibration of speed by mounting u on one of the poles of themagnetic mom a small copper shading coil. This pole is rotatable, sothat the torque generated by the shading coil may be VIP.

varied. The

motor is so designed that the shading coil normally operates practicallyin a neutral position, so that it has but very little e'fiect upon thespeed of the motor. The

speed may, therefore, be regulated byja" micrometer adjustmentforrotating the pole. and hence the shading coil, in one direction or theother. The use of the leakage flux-in the development of the motortorque does not entirely eliminate temperature er-- rors, which would bevery excessive if the.

motor depended upon the torque generated by copper' shading coils, ashas heretofore been the usual practice. I eliminate the temperatureerror in my novel form of induction electric motor by a thermostaticadjustment of the rotatable pole of the magnetic member. To this end. Ioperatively 5 connect a duplex metal thermostatic member to therotatable pole in such a manner thatan increase of atmospherictemperature will rotate the pole in a direction tending to increase thespeed of the disk armature,

thus compensating entirely any tendency to reduce the motor speed withan 'increase at temperature. and vice vers:

The novel features which I believe to be patentably characteristic of myinvention are definitely indicated in the claims appended hereto. Theprinciple of operation and mode of construction of an induction electricmotor embodying my presentinvent-ion-will be understood from thefollowing" description taken in connection with the accompan'vi'ngdrawing. in which:

t The figure is a diagrammatic view in perspectiveof anclect-ric motorembmlying my invention operatively connected to a-circnit timeintervals; r

. The motor comprisesfa U-shaped magnetic members? upon each leg ofwhich is mounted "an' electric current carrying coil (3. The coils-6 areconnected in series with each other and are adapted to be supplied withcurfroni the conductors-70f an alternating .cnrrent. circuit. v TheU-shapcd magnetic.

25 closet for closing an electric circuit at equal member is provided atits ends with two.

- poles- 8 and 9 separated from each other by a small air ga ofsubstantially. uniform width.-I The po e S is rigidly secured to themagnetic member, while-the pole 9 is secured :W shapedjmagnetic fmemben-The pole 9 carand isfpo'sitionedfto rotate in the air 'gap bet-ween thepoles 8 and? of the U-shaped msctic member i Tlie disk armature 12 is;'trther' so' positioned with respect' to the u-"sliaped magnet-idmemberthat it is sub-- the. magnetic member." 3 In otl'ier words the Idtskarmature is so positioned that it is cut member; The leakage flux ofthe U-shaped 'ma 'netic membcr is substantially ill-Phase the pole 9;

increase the speed of the disk armature, thus ;by-tli'e-?leakage fluxwhich ases fronrone. leg .to the other of the U- taped magnetic ing inthe coils 6. Th? maefitfilfipvment between the leakage tlux and the maintlnx cutting the disk armature develops a torque tending to turn thearmature.

The short-circnited coil it is arranged so to that in normal operationit occupies a practically neutral position. so that it develops littleif any motor torque. thus having little or no eti'ect on the speed ofthe motor. 1t will be seen that the speed of the motor may he changedone way or another byfrotating Rotation of the pole 9 thus serves as a,means for calibrating the speed of the motor. a

duplex or bi-metallic thermostatic memso her or bar l-L of any wellknown-design is connected to the pole 9. It will be observed that thethermostatic member 14 extends for the greater part substantially.parallel tothe legs of the U-shaped'ma'gnetic member and s .has atitsand of connection to" the le 9 a curved portion, being generally 0crooklike configuration. The thermostatic inem her is loosely positionedatits free end in a .1

groove 15 of a stud 16 secured .tofth'c U,- 0

shaped magnetic member. I u an increase I of the surrounding atmosp lel'IC temperature, the thermostatic member. l toperatc's, 1:;

to rotate the pole 9 in a direction tending to compensating entirely forany tendency to.- reduce the, speed of the disk armature 'occa sioned bythe increased teniperat-urc. il po a decrease of the surroundingtemperature;

the cited: of the thermostatic member-jl-t i j nstthe reverse.

' The rotatable shaft lgisoperativelyicon-i "I l nected to a gear 1'?through a tm in of reducw tion gearing 1S. .The-gear. 17 isseeured'atone end of a shaft- 19 while a canrzlfl isse cured atthe otherend of this shaft. follower 21 is secnred'to a -pivoted and isoperatively held in enmigeinen the'cam- :20 through the actionof ng- 23.The arm :22 is provided atone endwitl a fingers which is adapted toengage jajpiu 25 on a disk 26 loosely mounted onjt e shaft; 19. Rotationof the disk' flfiais limited ta one direction by the enmigeineut" of thepin .2 5 with the'fin ger 24- and in the otherilireclt 5" tton bv theengagementof a Iug-QT'with'a' stop-pin 28.- The disk armature of themotor rotates the cam :20 at substantially constant speed thecam-follower :21. drops off the shoulders of the cam surface, whereuponfinger 2-1. sponding to .the action of the spring 23, imparts a quickkick to the pin 23. Tltepinv 25 moves in a counterclockwisedirection inI25 responseto the kick imparted thereto; and engages a resilientcontact-member 29 of a pair of cooperating contacts arranged in anelectriccircuit 30. The cngmgement of, the

pin 25 with the contact-member :29 ctl'ects a in acounterclockwisedirection: Twice dnrtng'each revolution of-tlie cam .20 I20 momentaryclosing of the circuit 30; but

due to the balance of the disk 26 the pin 25 drops immediately back intocontact with the finger 2-1. It will thus be seen that the cooperatincontacts of the circuit 30 are momentarily closed each time apredetermined number of revolutions of the disk armature have beencompleted, that is, at

netic torque and damping must; neces arily have an efl'ect varyin'directly with the .-value 'of the flux and therefore the balance or theratio of flu: todamplng remams ub- 'stannally constant undervanations'of 'volta e such as occur in commercial circuits.

Ibe. speed of the motor is thus substantially constant :under allordinary conditions. The a motorjispecuharlv'adapted'for use-m elect-rical' demand a paratus but mavof; course be used with at vantage'wherever timeactuated or constant speed action or move-;

mentisdesired. 1

- I have explained mvinvention by illustrating and'describinga certainspecificiembodiment thereof." but it will be readilv' underst ood li v.tho so. skilled in the art that the inventionfmay be embodiedanother-forms than that shown and described. L'accordinglv do not wishto be restricted to the particular."construction or application'disclosedhereim'by way of example for the pur ofsettingforth'mvinvention in ac con agiceiwitlrf-tlie- 'atent statutes; The

terms bithc-appendm claims are. therefore.

not restricted to the precise structure disclosedlult are intended to'cover all changes andhnodifications 'within'the spirit and scopeof miinvention. r

.What' I claim as new and desire to secure by Letters Patentofthe'I'nited States. is': I 1. In an induction electric motor. amovable shading coil. and temperature responsive means able polecarrying a short ireuited coil. and means for moving said pole inresponse to changes in temperature.

In an induction electric motor. a rota-. table'disk armature. inductionmotive means tending to rotate-said armature, a short-ciroperativelyconnected to said coil. 3

2. In an induction electric motor. a movcuited coil associated with saidmeans, and a thermostatic member adapted to vary the efi'ectof saidshort-circuited coil upon said means.

i. In an induction electric motor. a rotatable disk armature.inductionmotive means tending to rotate said armature. a movable pole having ashort-circuited coil asociated with said induction motive means, andtemperature responsive means operativelv connected to said ole.

5. In an int uction electric motor. a U- shaped magnetic member havingits two legs uniformly spaced apart. a pole piece mounted on the innerend of each leg of said member. said pole pieces being separated fromeach other bv a relatively narrow air gap of substantiallyuniform widthwhile the distance between the lmiformly spaced legs of said member ismany timesgreater than the width of said air gap.'an electric currentcarrying c011 associated with said member, and a metallic disk armaturemounted for rotation in the air gap between said pole pieces andpositioned to be subjected to the influence of the leakage-flux of saidmagnetic member whereby a torque tendin to turn saiddisk armaturedeveloped by the 'ditference intime phase be-' tween the leakage flux of.said magnetic member the main flux acros said air 6. In an mductaonelectric motor, a magneticimemberhaing main poles separated l by arelatively-narrow air gap, electric current carrymg coil.asociat'ed'with said member, and a metallic disk -armature mounted forrotation in the air gap between said main. les and positioned to besubjectedto the influenceof. a leaka e flux from said magnetic member.the 1e11, of the air path of said leakage -flux being'many timesgreaterthan the width of the air gap between said main les whereby thereis a material'and an a rapt change in the time phase of the main flu:across said air-gap and the-leakageflux to which said-disk m ture issubjected. p

T. In an induction electric moto1,.a ma net-ic 4 member having.oppositely. positioned poles se arated by a 'small-airgap, one of saidp'o' es being: movable and carrying a short-circuited coil; an electriccurrent-carrying coil mounted on said member, and a -metallic diskarmature mounted for rotation in Slid air gap. and osit-ioned to besubjected to the influence o the leakage jinx 'of said magneticnremberwherebv a tor ue tending to turn suddlsk is developed 5' thephase displacement between theleakage tin: and the main flux across saidair gap.

8. In an induction electricmotor, a magnetic member having oppositelypositioned. poles separated by a small air gap. one of: said poles beingmovable and carrying a short-circuited coil. an electric current carrymgcoil mounted on-said member, a metallic disk armature mounted forrotation in said air gap. and positioned to be subjected to theinfluence of the leakage flux of said magnetic member whereby a torquetending to turn said disk is developed by the phase displacement betweenthe leakage llux and the main llux across said air gap, and temperatureresponsive means operatirely related to said movable pole.

9. In an induction electric motor, a magnetic member having oppositelypositioned poles. means for de elopingan alternating magnetic flux insaid magnetic member. a metallic disk armature mounted for rotationbetween said poles and positioned to be subjected to the inlluenceof theleakage flux of said magnetic member. said poles being so related withrespect to one another that the main flux thereacross ditt'ers in timephase from the leakage llux of said magnetic memher, and means forrendering the torque developed by said leakage and main fluxes amltending to turn said disk armature substantially independent of changescaused by temperature variations. 3 i

10. In an induction electric motor. a U- shaped ii'mgnetic member havingoppositely positioned poles separated by an air gap, oneof said polesbeing movable and carrying a short-circuited coil. an electric current.carrying coil mounted on said member, a metallic disk armature mountedfor rotation .in said air gap and positioned to be subjected to theinfluence of the leakage flux of said magnetic member \\'l1ereb \'-atorque tending to turn said disk armature is developed by the phasedisplacement between thevleakage flux and the lnain flux across said airgap. and a thermostatic member operatirely related to said movable poleand adapted to. adjust the position of said short-ciryuited coil inresponse to temperature variations,

11. In an induction electrio'motor, a mag-' netic member baringoppositely positioned poles separated by an air gap. one of saidpeniture variations.

In witness whereof. I have hereunto set my hand this id day of December.1914. CHESTER I. HALh- Witnes es Ronr. MC'LIJIR, K. D. Frrcn.

